Automobile Diesel Engine Conversion

[Kielanders]

I've searched and not found a thread on this, if there is one, apologies, give me a link, and nuke this thread.

I've got a small Isuzu truck that I've had for 18 years and needed no major work until last year, bought a rebuild kit for $400, and it runs like new.

So here's the question, is there a problem with taking a small diesel auto engine and using it for sailing applications in a freshwater cooling setup?

Thanks.

[DRFerron]

In theory, you can. However, auto engines are not designed to be in the type of marine environment that you'd find on your boat. Do people do it? Sure.

Something that always makes me think twice about putting a part made for automobiles into our boat is, if anything happens, knowing that I didn't use the part designed for the environment, would my insurance company make good on a claim?

[Passat]

I'd like to hear some info on this topic too!

[celenoglu]

Marine engines generally originate from truck or tractor engines. The difference is the ooling system and some modifications in the parts such as the piston rings and other parts that might be subject to salty water.

You can use a truck engine as a marine engine, but salt water ingress from the egsost will the main drawback.

[dabnis]

I think the Pathfinder marine diesel is based on VW diesel engines. Not sure if they use different camshafts or any other internal engine modifications in addition to normal "marinization" ( is that a word?) add ons. I worked on both the normally aspirated and turbo VW diesels, seemed fine for automotive use but have not had any experience with the marinized versions. I think Kuboto
tractor engines and other small industrial diesels are regularly used for marine applications but they started out as industrial engines to begin with. Marine use is a lot harder on an engine than automotive use, always running hard uphill and never getting a chance to breathe. It may not be practical for a DIY person to try to convert an automotive diesel after buying all the conversion parts, motor mounts and so on, and then finding out the automotive engine wasn't up to the task. As always, just my opinion based on my experiences, offered at no cost, and for what it is worth, and your mileage may vary.

Dabnis

[RobGallagher]

Is it just an urban legend that 1980's VW Rabbit diesel engines are still sought after for sailboat engines?
Bloke down the pub said they are bullet proof, run for ever, can still be found in junk yards, and that steel hulled cutter that stops by on it's run from Costa Rica to Main every spring has one with 30,000 hrs on it.

[tdw]

I believe that only Yanmar and Bukh of all the diesel engine producers (for small boats at least) are designed for marine use and not simply auto engines marinised.

Whether or not the work involved to convert would be cost effective, given you already have the original auto, I could not say. Maybe you'd be better off selling your engine and starting from scratch.

[Hudsonian]

Here's more of the VW/Pathfinder conversion: History of the VW Pathfinder Marine Engine

[dabnis]

From an earlier thread:

"I had a VW diesel Rabbit. When on a trip to Wyoming during
extremely cold weather before starting, which was very
difficult, needed a very small shot of ether, coolant would
weep out at the head gasket. After it warmed up a little the
leak stopped, with no further problem. I know, no ether with pre-
combustion chamber heads, but it was the only way to get it started
at 10 degrees below zero. I ran it for over 100,000 miles, no problems.
I think it was basically a converted gas engine, OK for automotive
use, but not sure about continous long term loading of marine use?"

"Right, I only used just a whiff and only in below zero
conditions. In "normal" conditions the glow plugs worked fine.
My daughter had a turbo diesel VW Jetta. After about 60,000
miles after climbing Donner summit or any other long grade
the oil pressure would drop to about 5 to 10 pounds at idle,
setting off the low pressure warning light. Heavier oil didn't
help. Either it was the lower end loosening up or the pump
wearing out? Other than that it ran fine, the turbo really helped
performance. I think it was the same basic engine as in the Rabbit,
maybe a little more displacement, and of course the turbo.
Again, not sure about marine use although in an earlier post Faster
said he had one in two boats with no trouble?"

The whole thread, a little long, but good info:

http://www.sailnet.com/forums/boat-r...ut-viable.html

Dabnis

[Kielanders]

Originally Posted by tdw

I believe that only Yanmar and Bukh of all the diesel engine producers (for small boats at least) are designed for marine use and not simply auto engines marinised.

Whether or not the work involved to convert would be cost effective, given you already have the original auto, I could not say. Maybe you'd be better off selling your engine and starting from scratch.

Oh, I wasn't going to use the existing engine from my truck, but it's my recent rebuild of that engine and the fact that I'm actively shopping for my first boat, that got me wondering about the practicality of doing a conversion.

I played around with the idea of building a kit-plane a few years ago, and always found interesting the lengths that people went to in order to do an auto/aero conversion. Some really creative and cost effective solutions were employed to accommodate individual dreams.

Since I've been shopping sailboats, I've not seen much discussion that's similar - though a marine capable engine can be as spendy as a small certified aero engine from a dedicated manufacturer. It was often said that 75% of the cost of an aero engine was liability insurance for the manufacturer.

Of course, depending on conditions, an engine failure while sailing can be catastrophic, when all is said and done, I'd rather take a chance on an engine failure sailing over flying.

I'm not married to the idea of a conversion for sailing, just wondering about it.

Is there anything particularly unique concerning working on a marine engine from one of the major manufactures, skills that I might not have from doing auto rebuilds? Or is it just a matter of using certified parts for marine environments?